Berlin 2008 – wissenschaftliches Programm
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SYEC: Symposium Exact-exchange and hybrid functionals meet quasiparticle energy calculations
SYEC 2: Exact-exchange and hybrid functionals meet quasiparticle energy calculations II
SYEC 2.11: Vortrag
Donnerstag, 28. Februar 2008, 16:30–16:45, A 053
Electronic correlation in 3d transition metals beyond GW: The FLEX method — •Andreas Gierlich1, Arno Schindlmayr1, Stefan Blügel1, and Václav Drchal2 — 1Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany — 2Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 18221 Praha 8, Czech Republic
The GW approximation is currently the most successful ab initio approach to electronic excitations and spectroscopies of semiconductors and simple metals. However, it ignores spectral features resulting from higher-order correlation effects in the localized 3d orbitals of transition metals, such as the 6 eV satellite in the photoemission spectrum of nickel. Furthermore, exchange splittings and 3d valence band widths of transition metals often deviate from experimental measurements. The fluctuation-exchange (FLEX) method is a diagrammatic technique that describes additional two-particle scattering processes beyond those contained in the GW approximation. We have developed a simplified FLEX implementation designed to describe electronic correlation in 3d transition metals. Starting from density-functional calculations within the full-potential linearized augmented plane-wave scheme, we apply the FLEX method as a perturbative correction to include the two-particle correlation effects in the self-energy of the 3d electrons. The resulting equations are solved self-consistently within dynamical mean-field theory. We have applied this scheme to selected materials with intermediate correlation strength and present illustrative results.